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Good Suggestion Heaterman, she Lost "Freon" again!

With all of these issues, freeze protection is not what is needed. I would suggest a new hvac company.

She had a new compressor installed Wednesday the 12th (leak where power line enters sealed compressor hsg), and I called her Saturday,15th to check-up.

Outdoor unit was running and it was 80 inside and 80 outside. I called Aztil emergency number and they came out and put 4 lbs of "freon" in, and the overall manager promised to have their best guy out Monday morning to die check system for the real leak.

Why the heck didn't they test for leaks after the fixed the one leak? Not standard practice?

A new hvac co is a good idea. For now I'm going to push that they install the freeze-stat with no charge.

I used the aop company search, and Atzil was not included in the results. What can I conclude?

Well, this freeze problem was "fixed" by replacing a compressor that was leaking where the power lines entered.

Then, 3 days later, she lost cooling again !!!! This was from a coolant leak at a coupling on the suction line, NEAR the new Compressor !!

I call the Tech-Boss, and he assured me that after each leak was repaired, the system had to hold vacuum for 30 minutes.

So I guess either the 1st repair was not followed by a vacuum teat and the 2nd leak was still active, or, the 2nd leak occured due to a bad soldered joint by the 1st guy, which leaked in a coulple days.

So I'm still looking for a freeze stat, since leaks are a way of life for now, and my 89 yo Mom is not going to notice it until her cloths are soaked.

But I'm looking for a freeze stat that attaches to the suction line near the A-coil in the attic. But it has to have an alert light that can be mounted about 10FT away, in the basement, so she knows there is a problem.

Well, this freeze problem was "fixed" by replacing a compressor that was leaking where the power lines entered.

Then, 3 days later, she lost cooling again !!!! This was from a coolant leak at a coupling on the suction line, NEAR the new Compressor !!

I call the Tech-Boss, and he assured me that after each leak was repaired, the system had to hold vacuum for 30 minutes.

So I guess either the 1st repair was not followed by a vacuum teat and the 2nd leak was still active, or, the 2nd leak occured due to a bad soldered joint by the 1st guy, which leaked in a coulple days.

So I'm still looking for a freeze stat, since leaks are a way of life for now, and my 89 yo Mom is not going to notice it until her cloths are soaked.

But I'm looking for a freeze stat that attaches to the suction line near the A-coil in the attic. But it has to have an alert light that can be mounted about 10FT away, in the basement, so she knows there is a problem.

Is there any such thing?

Thanks for all the help.

Theres your problem! Find another contractor that knows what a micron gauge is for and how to use it!

using a vacuum test for a leak check is stupid , its best to pressure test with nitrogen then bubble check your braze joints

In most respects, I agree with carmanacman because the micron gauge will climb higher due to minute amounts moisture yet left in the system.
Therefore, how well it holds the pulled down microns is more of a test on whether the refrigerant system is sufficiently evacuated.

Always do a nitrogen pressure test prior to evacuation procedures.

This is how some procedures are performed:
When a system has been evacuated below 500 microns, the pump is valved-off with the micron gauge connected, if the vacuum rises to 1500 microns and stops, there is moisture remaining in the system. If it rises above 1500 microns & continues to rise there is a leak. You should allow at least 15 minutes after the pump has been shut off for an accurate micron gauge reading. When a system will not evacuate below 1500 microns there is either a lot of moisture in the system or there is a refrigerant system leak. Keep the oil changed in the vacuum-pump & make sure it is working properly.

The R-410A systems ought to be double evacuated; some even use a triple evacuation procedure like is used on low-temp systems.
Purging with dry-nitrogen prior to evacuation & purging between pump-downs helps speed-up the evacuation process.

The freeze stat is not the answer when you have a PROBLEM, which you do. You will end up doing a lot more damage to her system by allowing it to cycle on and off while all the time it is low on refrigerant. If your current HVAC company can't properly identify and fix the problem(s), fire them and hire a company that is competent. Pressure testing and properly evacuating a system is the most basic of refrigeration procedures. It does not take fancy, exotic, super expensive equipment. Any company installing AC equipment MUST have the tools AND the expertise to do these things. No wiggle room here, zero, nada, zilch, NONE.

The freeze stat is not the answer when you have a PROBLEM, which you do. You will end up doing a lot more damage to her system by allowing it to cycle on and off while all the time it is low on refrigerant.

Thanks for the pos. I have thought about that cycling issue, and I spent an hour trying to find a freeze-stat with a simple warning lite that my mother could see, but I did not find anything with a light. But I wondered how much system damage was caused in building up 6" of ice on the evaporator? I assume it would try to run and then kick out, but perhaps not?

If your current HVAC company can't properly identify and fix the problem(s), fire them and hire a company that is competent. Pressure testing and properly evacuating a system is the most basic of refrigeration procedures. It does not take fancy, exotic, super expensive equipment. Any company installing AC equipment MUST have the tools AND the expertise to do these things. No wiggle room here, zero, nada, zilch, NONE.

I agree. Looking at the Work Orders, they did a vacuum test after the 1st leak fix (compressor replaced), but there was no comment about a vacuum test on the 2nd leak fix (suction line by the compressor).

The compressor was sent back to the factory, and I'm in the process of asking them to do a failure analysis on this 1 year old compressor that leaked at the seal for the power line.

Regarding a new company, it's easy for a pro like you to quicky come up with a better company. But she is 1000 miles away, and I'm a professional mechanical engineer that actually does hard core engineering, vs doing the typical cook-book code reading and/or managing, but I've only learned about H&V stuff here, and dealing with the contractor, Atzil. The local distributer, Gemaire, is giving me a list of companies that they feel would result in better system reliablility.

One question: they are supposed to do a vacuum test after breaking the line. How long is it supposed to hold 500-1000 microns of HG, and what if any is an acceptable vacuum drop in the test period ??